I wish the Genesis supported s-video out of the box, considering it has pretty poor composite output. I think the difference would be more striking than with the SNES since, relatively speaking, it has pretty good composite, although this is just conjecture since I've never seen an s-video modded Genesis in action. I'm not interested in mods myself, but I'll always try to take advantage of the best that a system supports naturally, even if the difference isn't that significant.